docs: def as_png_data_uri(matrix, version, scale=1, border=None, color='#000',
                      background='#fff', compresslevel=9, addad=True):
      """\
      Converts the provided matrix into a PNG data URI.
  
      :rtype: str
      """
      buff = io.BytesIO()
      write_png(matrix, version, buff, scale=scale, border=border, color=color,
                background=background, compresslevel=compresslevel, addad=addad)
      return 'data:image/png;base64,{0}' \
                  .format(base64.b64encode(buff.getvalue()).decode('ascii'))